Loader for trucks

ABSTRACT

A loader for trucks or other vehicles which can be automatically operated, and which utilizes a loading slide which is initially inserted into a vehicle to be loaded, and which is moved automatically out of the vehicle as loading commences. An interlocking means can be provided for controlling the various functions of the loader assembly, and in this manner the loading can be automatic.

United States Patent Hanson Apr. 17, 1973 LOADER FOR TRUCKS 3,221,91212/1965 McWilliams ..214/514 Inventor: Douglas R. Hanson, 1720 9th3,599,262 8/1971 Carder et a] ..2l4/38 BA X nue, Mmn- 5 5303 PrimaryExaminerRobert G. Sheridan [22] Filed: May 7, 1971 Attorney-Dugger,Peterson, Johnson & Westman [21] Appl. No.: 141,225 [57] ABSTRACT Aloader for trucks or other vehicles which can be auil...214/4l,;61;1/337/B02 tomaficany operated and which ufilizes a loadingSlide [58] Fe'ld B BA which is initially inserted into a vehicle to beloaded, l C 38 D 41 51 6 and which is moved automatically out of thevehicle as loading commences. An interlocking means can be provided forcontrolling the various functions of the [56] References Cited loaderassembly, and in this manner the loading can UNITED STATES PATENTS beautomatic- 3,337,066 8/1967 Reed et a] ..2l4/38 C 11 Claims, 11 DrawingFigures yes PATENTEUAFR I 71975 sum 3 OF 4 -7 1.2 lm w PM, w l.

I N VEN TOR.

fi k m F mu n? m% My B W W LOADER FOR mucus BACKGROUND OF THE INVENTION1 Field of the Invention.

The present invention relates to vehicle loading devices.

Prior Art There have been a number of loading devices in the prior art,which are utilized for loading vehicles such as trucks with pallets orpalletized material. For example, U.S. Pat. No. 3,337,066 shows avehicle loading and unloading apparatus which is quite costly to make,cumbersome in operation, and includes many components that must beoperated for the loading operatron.

The idea of using a two direction positionable conveyor system forloading devices is shown broadly in U.S. Pat. No. 1,608,213, but this isused for unloading railroad cars. An external bed leveling mechanism fortrucks is shown in U.S. Pat. No. 3,397,802, and automatic handling ofpalletized loads is shown in U.S. Pat. No. 3,421,641. U.S. Pat. No.2,139,667 shows a form of a loader-assembler which preforms the loadsand deposits each load in turn into the loader and then the loaderdeposits the load into a truck.

Another type of leveling device for truck loading and unloading is shownin U.S. Pat. No. 3,250,408. There are various other types of palletarranging devices and the like in the prior art.

SUMMARY OF THE INVENTION The present invention relates to a loadingdevice. The device can be completely automated, and is capable of beingmoved to a number of different stations, and uses a loading slide memberwhich inserts into the vehicle to be loaded, and which automaticallyretracts as the loads are inserted into the vehicle.

The invention further comprises adjusting means for adjusting thecorrect height of the loader assembly, and means for moving the loaderassembly transversely to a plurality of different loading positions. Asensor for insuring that further loading will not occur when room leftin the truck is not sufficient to take additional pallets being loadedis provided.

The device is simple to make, and easily operated and eliminates much ofthe mechanism of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of aschematic layout of the arrangement of the present invention;

FIG. 2 is a view taken substantially on line 2--2 of FIG. 1, with aloading slide shown inserted into a truck and two pallets partiallyloaded thereon;

FIG. 3 is a top plan view taken as on line 3-3 in FIG.

FIG. 4 is a fragmentary enlarged sectional view taken as on line 4-4 inFIG. 3;

FIG. 5 is an enlarged side view of a typical support device used withthe present invention;

FIG. 6 is an end sectional view of the conveyor support table andloading slide of the present invention;

FIG. 7 is an enlarged detail end sectional view of a conveyor slidedrive;

FIG. 8 is a side view of drive sprockets for a slide drive;

FIG. 9 is an end sectional view of the device of FIG. 8; and

FIGS. 10 and 11 are schematic representations of a control arrangementused with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A trailer loading arrangementillustrated generally at 10 is, as shown, used for loading semitrailerbodies or other trucks or vehicles. A typical trailer is illustrated at11. Means are provided for arranging load pallets (or crates, boxes orother items) for loading the truck. schematically, one such arrangementcomprises a pallet delivery conveyor 12. A pusher 15 is provided formoving pallets from the conveyor 12 into a pallet stacking device 13,wherein pallets coming from member 12 are stacked vertically, andarranged in a two high, two wide stack. The pusher 15, or anotherseparate long stroke pusher moves the pallet stack onto a fixed crossconveyor 14. The conveyor includes a pusher 16 which is actuated by adriven chain 27 for moving stacks of pallets toward a movable set ofconveyors. The stacks of pallets are deposited on a first movable crossconveyor table 17, and are moved through a suitably driven pusherconveyor shown generally at 18, operating on scotch yoke principledriven by a chain 29, so that the pallets on the conveyor table 17 aremoved in direction as indicated by the arrow 21. The conveyor 17 ismovably mounted on a pair of tracks 22,22 through suitable wheels, shownonly generally at 23. The wheels are at the outer end of this conveyortable 17, and the end of the conveyor table opposite from the wheels ismounted through a suitable ball joint arrangement 25 to a main loadingtable assembly 26. The loading table assembly 26 is also mounted onsuitable rails illustrated generally at 26A, through four wheels. Theentire conveyor 17 and loading table assembly 26 can thus be moved backand forth along these tracks to different transverse positions forloading trailers 11 in different locations from that shown. The drivemeans for moving the tables will be more fully explained. The means forstacking the pallets and moving the pallets onto the conveyor 17, andthe means for moving the pallets toward the loading table 26 can be anydesired type of devices. The pallet arrangers are well known in the art.It should be noted that both the table 26 and the cross conveyor 17 moverelative to the conveyor 14, and the stacker 13, and the pallet supplyconveyor 12 which do not move transversely.

The pusher 16 for conveyor 14 is operated with a scotch yoke assemblyfrom the chain 27 that is driven with a motor 28 shown onlyschematically. The pusher 18 for the conveyor table 17 is driven with apin carried by the chain 29. Chain 29 is mounted over sprockets mountedon the conveyor table 17 and moves the pusher 18 when the chain isdriven by a motor 30. The pin conveyors operating the pushers 16 and 18,are identical to the drive for a conveyor that operated in connectionwith the loading table 26, and thus the construction is shown onlyschematically.

The main loading table 26 comprises a main support table or frame 33.The support 33 includes a table top member 34, and the support wheelsfor the support table are mounted with respect to the top 34. Supportwheels 35A and 35B are mounted at the outer end,

(away from truck 11) and wheels 36B and 36A are mounted at the end ofthe table adjacent the trailer 1 1. The wheels are supportedindividually with vertically adjustable screw jacks but wheels 35A and36A are connected with an axle, and the wheels 35B and 36B are alsoconnectedwith an axle. These screw jacks are shown typically in FIG. 5,and are individually operated for height adjustment.

The table top 34, as shown, supports brackets 40, one for each of thesupport wheels, and each of the brackets in turn mounts a screw jacketassembly 41. In FIG. 5, the wheel 35B is shown, and this is the powerwheel for the unit. The screw jacks 41 are conventional screw jacks, forexample the screw jacks sold by Duffnorton Company, Charlotte, NorthCarolina, and are each operated with a separate electric motor 42A or428. The motors 42A are used on the wheels on the outer end of the unit(away from the trailer), and the motors 42B are seen in FIG. 6 at theinner end of the unit. If desired the screw jacks for the wheels 35A andB can be connected with a shaft for simultaneous operation, as can thejacks for wheels 36A and B.

The Wheels 358 and 36B are mounted onto axle 45, and the axle 45 ismounted in suitable bearing members 44 which are attached to therespective ends of the screw jacks 41. The axle 45 is made of twosections connected together with an electric clutch 43 which is normallyengaged so that the axle sections of axle 45 must rotate together as aunit, but the clutch can be released upon actuation by an operator topermit the wheels 35B and 36B (which are drivably mounted on oppositeends of the axle) to move independently of one another. The table 33 isdriven along tracks 26A through the use of an electric motor 46operating through a chain drive assembly 47 to the transverse axleassembly 45.

The wheels 35A and 36A are connected together with a transverse axleassembly 50 that extends between the wheels 35A and 36A and supportsthem. The axle 50 is also supported in suitable bearing housings 44mounted on the respective screw jacks. The bearing assemblys 44 permitthe axles to rotate freely. An electric clutch assembly 43 is used inthe axle 50 to permit individual movement of the wheels 35A and 36A. Theclutches 43 permit cocking the table 26 slightly along its tracks 26A toobtain perfect alignment of the table with the tailer 11 is desired. Themotor 46 can be driven to drive the entire table assembly 26, which willpull the conveyor 17 along the tracks 22 to properly position the unitbehind a trailer to be loaded.

The table assembly 33 has side members 51 and 52, respectively fixed tothe table top 34, and these side members go upwardly above the table top34 and are fastened thereto to provide side guides for a loading slideor tongue illustrated generally at 55. The side guide members keep theslide 55 in position on the table top. The slide 55 comprises a movablemember that is mounted for movement along the table top, and may bedriven through the use of friction drive wheels illustrated generally at56 which support the slide. The slide 55 is made of two spaced plateswhich are reinforced and supported by desired web members.

Referring specifically to FIG. 6, it can be seen that the drive wheels56 are mounted on cross shafts 57 and extend across the table. Theshafts 57 are supported in suitable bearings 58 so that the wheels 56stick up above the table top 34 a desired distance. The bottom plate ofthe slide member 55 rests on these wheels. The shafts 57 (and thuswheels 56) are all driven together with suitable chain arrangementsshown at 60. A reversible drive motor 61 is used for driving a key shaft57 shown in FIG. 6, through a chain 62 driving up to a triple sprocket63. The triple sprocket 63 includes a sprocket for the chain 62, and forchains going to the shafts 57 in each direction from this key shaft.

The triple sprocket 63 is mounted onto the shaft 57 with a oneway driveclutch 64 that permits the sprocket to drive the wheels 56 in directionto drive the slide 55 toward the truck 11 but permit the wheels 56 tofree wheel in opposite direction. However, in order to. also provide areverse drive of the wheels 56, an electric clutch 67 can be mountedbetween the outer end of the key shaft 57, and the outer sprocket or endof triple sprocket 63 as shown in FIG. 8. The electric clutch 67 isnormally disengaged to permit free wheeling reverse movement of thewheels 56. The clutch normally permits the sprockets to drive the slidein forward direction when motor 61 is driven as indicated by arrow 65and all of the wheels 56 to free wheel to permit the slide 55 to move inopposite direction because of the free wheeling oneway clutch 64. Whenthe electric clutch 67 is energized, it is made to lock the sprocket 63to the key shaft 57 so the sprocket 63 drives in either direction ofrotation. By reversing the direction of rotation of reversible motor 61,the wheels 56 can then be reversed for moving the slide 55 out of thetrailer 11 when the last pallet has been loaded into the trailer.However, it should be remembered that the electric clutch 67 is normallydisengaged and the wheels 56 will free wheel when the slide member ispushed in opposite direction from the arrow 65. The electric clutch 67is on the drive shaft that is directly above the motor 61, and theoneway clutch is also only on the triple sprocket 63. The chainarrangement is shown generally in FIGS. 8 and 9.

The slide assembly 55 as shown is provided with rollers 70 suitablyrotatably mounted thereon and extending downwardly below the bottom wall71 of the slide 55. These rollers can be mounted in any suitable manner,and do not engage the table top 34 when the slide is resting on therollers 56, but as shown in FIG. 4 will ride against the bottom 91 ofthe trailer 11 when the slide is pushed forwardly into the trailer, asshown in FIG. 3. In addition, the slide member 55 has a top wall onwhich suitable transverse rollers 74 are also mounted. The rollers 74protrude slightly above the top wall of the slide member 55 and arerounded at their ends to permit the pallets to be slid onto the rollers.The rollers 74 are made up in two rows on the sides of the slide so thatpallets skids can ride on these rollers. The pallet skids can be slid inaxial direction of the roller when they are being loaded from theconveyor 17 onto the slide 55. It should be noted in FIG. 6 that thetable 17 is mounted at a sufficient height so that pallets being skiddedalong the table 17 will slide across these rollers 74 and be positionedon the pallet slide.

The slide member 55 also has a pusher device 77 mounted therein forlongitudinal movement therealong. The pusher device 77 has a slot 78defined in the center thereof (see FIG. 4), and the slot 78 houses a pin79 which is attached to an endless chain member 80. The chain 80 ismounted over a pair of sprockets 81 and 82 respectively, which aremounted at opposite ends of the slide member 55. A motor 83, which isshown schematically, is used to drive the sprocket 81, to drive thechain 80 in its endless path about the sprockets. At the same time, thepin 79 will be moved with the chain and the pin will ride in the slot 78and move the pusher member 77 along the slide member 55. A stabilizingbar 83 is attached to the pusher 77 and has a pair of pins 86 thatextend down into a slot 87 through the top wall of the slide member 55to stabilize the pusher member in its path of movement, as the pushermember 77 moves back and forth. It should be noted that this action ismuch like a scotch yoke, and when the pin 79 reaches the end of travelaround'sprocket 82, it will reverse direction and the pusher member 77will also reverse direction and go back toward the outer end of theslide 55. When the pin 79 has traveled down to the sprocket 81, the pin79 will again move to the opposite end of slot 78, and the pusher 77will reverse direction and go back toward the inner end or tapered endof the slide member 55.

Thus the pusher member can be used for pushing anything that is restingon the top of the slid member 55 and it will push items along the lengthof slide 55. It should also be noted in FIGS. 6 and 7, that an invertedchannel shaped center support 90 is mounted onto the bottom plate 71 ofthe slide member 55. The support 90 extends between the side reaches orportions of the chain 80 to support the pallets as they are slidtransversely across the opening which is provided for the chain 80 andthe connected pin 79, without dropping in the hole for the chain 80. Theslot 87 for the pins 86 of stabilizing bar 83. is very narrow so thatthe pallets can slide across the slot.

The pallet support blocks, which are shown in dotted lines in FIG. 6,are arranged so that when the pallets are properly positioned they willbe resting on the rollers 74 on the top of the slide member 55. Themounting for the rollers 74 can be of any desired type. It should benoted the ball joint 25 for the conveyor 17 is shown in FIG. 6. Thetable 17 can tilt or twist to accommodate different heights of theloading table 26. When the trailers are to be loaded, a plurality ofpallets illustrated generally at 95 are stacked two abreast and two highby the stacking device 13. The motor 61 is driven to drive the slide 55into the trailer 11 as will be more fully ex plained.

When in operation, the stacker 13, conveyor 14 and pusher 15 arecontrolled as shown schematically in FIG. 1, and an interlock betweenthe stacker and first conveyor 14 can comprise a system whereby a cammember shown schematically at 27A is carried by the chain 27 for thepusher 16 on conveyor 14. The cam will operate a limit switch 278 whenpusher 16 is in its home (retracted) position, to close a set ofcontacts, as shown in solid lines in FIG. 1. A stack complete" limitswitch 13A also is in the same circuit to the pusher 15. A furtherinterlock to insure that conveyor 17 is ready to receive additional loadalso can be in this circuit. Assuming that the pusher 18 is properlypositioned, when the stack complete limit switch 13A is closed, and theproper set of contacts in switch 273 are also closed, the pusher 15 willoperate to move a two high, two wide pallet stack out onto the conveyor14 in front of the pusher 16. When the pallets are in their properposition, they will close a limit switch 27C which will operate througha time delay relay 27D to energize motor 28, as shown schematically. Thetime delay 27D is present to insure that the pusher 15 is home beforepusher 16 is opeated. Motor 28 drives chain 27 and this will move thepusher 16 against the pallets on the conveyor 14. Cam 27A moves awayfrom its home position and this will permit the switch 278 to go to itsnormal position closing a second set of contacts, completing anindependent circuit to the motor 28, even after the pallets have beenmoved away from the switch 27C. This will mean the motor 28 willcontinue to drive until the chain 27 has again completed its circuit ofmovement and the cam 27A has moved switch 27B back to its solid lineposition as shown in FIG. 1, and has broken the circuit to the motor 28.There will be no pallets closing the switch 27C, and the motor 28 willstop until the switch 13A, is again closed (and the interlock formconveyor 17 indicates ready) operating pusher l5 and moving pallets toclose the switch 27C.

The same type of interlock is used to operate the conveyor 17. A cam 29Ais shown schematically on chain 29 for the conveyor pusher 18. This cam29A operates a switch 298, which is shown when the cam is in a homeposition, will move the switch 29B to its solid line position shown inFIG. 1, and will break the circuit to the motor 30. The switch 298 mayhave another set of contacts which as shown supplies the interlocksignal to the circuit for psher 15. As shown in FIG. 1, a limit switch29C is already operated by pallets shown on dotted lines on theconveyor, which are moved there by the pusher 16, and as shown in solidlines this limit switch is in its closed position because the palletsare in place, completing a circuit to the motor 30 through a time delayrelay 29D. Motor 30 will drive the chain 29. Once the cam 29A is movedaway from the switch 298, the switch 29B will move to position tocomplete a circuit to the motor 30 independently of the switch 29C. Thusthe pusher 18 has moved to engage the pallets on the conveyor 17, andhas moved the pallets away from the switch 29C, even though that switchwill open, the 1 motor 30 will continue to run until the chain 29 hastraveled in its path back to home position so that the cam is back toposition to move the switch 298 to its solid line position and break thecircuit to the motor 30 until an additional set of pallets are placed onthe conveyor 17. When the pusher 18 has been retracted sufficiently (forexample to its home position) the interlock to conveyor 14 will indicatethat this conveyor 14 can again operate. An interlock also is providedfrom the motor circuit for motor 30 to the motor 84 so that the pusher18 will not be operated until the timing is proper to insure that thepusher 77 will be out of the way when any pallets are psuhed by thepusher 18 onto the slide 55 As shown in FIG. 10, for operation of theconveyor on slide 55, a normally open limit switch 93 is mounted ontable 33 aligned with the conveyor 17. The switch 93 will be closed whenthe pallets are properly positioned on slide 55 by conveyor 17. Thiswill energize motor84, through a time delay relay, causing chain to run.To insure that chain 80 stops with pusher 77 retracted, the chain 80also carries a cam 94 which controls a normally closed limit switch 99.Assuming the pusher 77 is in its retracted position, switch 99 would beas shown in dotted lines, and switch 93 would also be open it no palletsare properly placed on the slide. This portion of switch 99 can be usedas the interlock signal to the motor 30. When the pallets are placed onthe slide 55, by conveyor 17, the pallets cause limit switch 93 toclose, energizing the motor 8 3 and driving chain 80 and pusher 77. Thecam 9 will then move off limit switch 99 permitting the switch to closea circuit to motor 84. The motor 89 will remain energized after thepallets have been moved away from switch 93, have been pushed off theslide and until the cam again gets to its home position.

Once the pallets are positioned on the slide 55, (assuming the slide isalready in the trailer) and with the motor 84 running, the pusher 77will be pushed through the pin 79 acting in slot 78 to engage thepallets 95 and move them into the trailer along the slid member 55. Oncethe pallets are moved by the pusher 77, the first group of pallets willengage the end wall 96 of the trailer, and when this happens the palletscan be moved no further, but the pusher 77 will still want to movebecause the pin 79 and the chain will not have gone around the endsprocket 82 yet. This will cause a reaction to occur tending to push thepallets against the wall 96 and at the same time the reaction on theslide 55 will cause the slide to move backwardly as indicated by thearrow 97 the required distance to slide the pallets off the end portion98 of the slide 55 down onto the floor of the truck. The free wheelingoneway clutch 64 permits this rearward movement of the slide 55.

After the pallets are clear of the end of slide 55 the pusher 77 willthen be reversed in direction as previously explained when the pin 79passes over to the other side of the slot 78 and reverses in directionof movement with the chain 80. The pusher 77 will be moved out of thetrailer and rununtil the switch 99 is opened by cam 94. In the meantime,additional pallets 95 will be assembled by the stacker 13 and conveyor14, and may be moved onto the conveyor 17 when the interlock signals areproper. After the pusher 77 has cleared the table 17 as the pusher movesrearwardly, (as shown when cam 94 actuates switch 99) the motor 30 willbe permitted to run and the pusher 18, which operates in the same manneras the pusher 77, will push the pallets onto the slide 55, again andclose switch 93. The pusher 18 will move back toward its home position.The pusher 77 will again be driven as described and move toward thetrailer to engage the new stack of pallets, and push them onto thetrailer, where they engage outer sides of the previously loaded palletsas shown in FIG. 2. The reaction will cause the slide 55 to moverearwardly again because of the free wheeling wheels 56. The truck walland previously loaded pallets provide a resistance to movement of thepallets on slide 55 and the reaction causes slide retraction. Thisloading operation will continue, and the slide 55 will continue to bepushed back out of the trailer automatically. To specifically go througha cycle of operation main power will be turned on and the slide 95 willbe retracted when starting. The conveyor will be jockeyed behind atrailer to be loaded by operating motor 46.

Referring to FIG. 11, the slide extender control swtich 104 will bepushed to its "in position "which will drive motor 61., and aspreviously explained, drive the slide member 55 into the interior of thetrailer so that the slide 33 goes to its full in position. The screwjacks are made so that they will be in their full up position, thuslifting the slide 55 high enough to clear any trailer. The extendermotor control also operates servo lockout relay 107 which locks out ordisables automatic circuits which are to be explained. The motor 61 willcontinue to drive until a limit switch 105, which is positioned at theinner end of the slide, contacts the front wall of the trailer. Switchshuts off the motor as, and at the same time de-energizes the servolockout relay 197 and shutting off the motor 61. When the servo lockoutrelay 107 is disabled, the automatic controls including amplifiers andcircuits illustrated generally at 198 will be energized. The slide 55will still be raised from the trailer floor.

These automatic controls include front pressure or load sensors locatedon the left and right side respectively of the forward roller 79 tosense load on the front roller 79 for the slide 55. These front pressuresensors are indicated in FIG. 4 at 103. Also intermediate pressuresensors 106, are positioned on opposite sides of the slide to sensepressure or load on the ends of a center roller 70, for example a rollerfour or five rollers back from the forward end of the slide. Thesepressure sensors 193 and 196 are solid state pressure sensors of astrain gage or variable resistance type which deliver a signal whenthere is load on the rollers to which they are attached, or which theymonitor, and supply signals to the servo amplifier and junction boxassembly 198. The amplifiers and sensors are commercially availabledevices. The signals from the sensors are used, through the servoamplifiers, to operate the jack motors 42A and 12B of the unit. As soonas the swtich 195 has been opened, the sensors 193 and 196 will beoperable to operate the jack motors 42A and ass individually and becausethe rollers 79 are raised from the trailer floor and not under load, thejacks will lower the table 26 and thus lower slide 55 downwardly ontothe trailer floor until the sensors 103 and 106 indicate that they areall contacting the floor. This means the slide will be resting on thetrailer floor. The sensors operate the jack motors until they each aresupporting substantially equal load. Then the jack motors will be shut05. The slide will be ready to use. Switch 195 shuts motor 61 out of thecircuit completely, once it has opened, and the automatic operation willcontinue. The pallet conveyors can start moving pallets onto the slide55 as described. The pusher 77 will be run through interlock circuits,to load pallets into the trailer and at the same time the slide will beautomatically backed out because of the reaction force on the slide.

When the roller 79 on which sensors 106 are mounted clears the trailer,a switch having a wheel that rides on the trailer floor will cut thesensor 106 out of the circuit. The switch 129 controls relays so it iseffective only after it has once contacted the floor of the trailer orbecomes "set." Then when it subsequently clears the floor of the trailerit will disable sensors 106 and has to beset again in the next cycle tobe operable.

As the unit loads, the backing out of the device slide will continue asthe pallets are loaded until a trailer full sensor 101 clears the end ofthe trailer, and operates a switch to drive the extender motor 61 inreverse direction. This switch will also energize the clutch 67 and willenergize the servo lockout relay 107 to prevent automatic operation ofthe pressure sensors and jack motors. The trailer full sensor can merelybe a limit switch that has a wheel on the actuator arm (as can switch120) and which is positioned adjustably on the slide. The position ofthe sensor 101 is adjusted for pallets of different sizes. At the timewhen the space left in the trailer is less than that needed for onestack of the pallets being loaded, the wheel for sensor 101 will dropoff the bottom of the trailer, actuating the sensor 101 to indicate thatthe trailer is so full it will not hold any more pallets. The electricclutch energization at this time is energized to insure that the motor61 will drive the slide 55 rearwardly through the wheels 56, all the wayback to its home position. Also, the conveyors i7 and 14 will bedisabled. At the time the slide reaches its home position, limit switch109 will be contacted and will break the circuit to the motor 61, theservo lockout relay 107 and clutch 67. At the same time, a second jacksup switch 1 is actuated to a closed position by the movement of theslide 55 to its home position. This swtich 110 is used to reverse thenormal operation of the jack motors 42A and 42B and to cut the switch120 out of the circuit for sensors 106 so that the sensors 103 and 106,which are not now under load, (and which are operable when relay 107 isdisabled) will instead of directing the jack motors to lower, willdirect the jack motors to raise the table assembly 26 to its full upposition. When it gets to its full up position, upper jack limitswitches illustrated generally at 42C and 42D, will open, and theselimit switches, which sense the jack position, will shut off the jackmotors.

The entire table 26 can then be moved by motor 46 to a new trailer andthe process repeated.

It should also be noted that the jacks for motors 42B and 42A are alsocontrolled by lower limit switches 42E and 42F, respectively as well sothat the jack motors will be shut off if they lower to their lowestpermissable level under opeartion of the sensors 103 and 106.

The retraction of the slide 55 to its home position can also be utilzedas a signal for shutting down or disabling all circuits to the conveyorsso that there will be no further loading until manually restarted.

It should be noted that the sensors 103 and 106 will sense movement ofthe rollers 70 and of the slide 55 away from the trailer floor. Thus ifthe trailer settles during loading and for example the sensor 106, whichis on a middle roller, moves away from the trailer bed, or is notsupporting its share of the load, the respective sensor will deliver asignal through servo amplifiers 108 to adjust jack motors 42A or 4213properly to get the proper leveling and sharing of load. Also, when twoseparate sensors on opposite sides of the slide are utilized, theindividual jack motors can be operated to correct for any twisting ortilting of the trailer transversely as well as movement in fore and aftdirection. This will keep the slide perfectly level at all times throughthe use of the sensors 103 and 106. The cam 94 on chain 80 can also beused, if necessary or desired to operate a disabling circuit for bothsets of sensors 103 and 106 when pallets are on the slide so that theleveling action takes place only when the slide is unloaded.

This would prevent excessive shifting of the table 26 with pallets onthe slide. However, the sensors themselves can be selected to block outsignals which indicate high loads and be sensitive to low loads only toachieve the same objectives. The entire unit can be controlled asdesired, and the use of a slide member, with a pusher conveyor givesproper loading and easy control with a minimum of parts and expense.

It also should be noted that the swtich 104 can be used to manuallyretract slide 51 (out position). Actuating the switch also will energizeclutch 67 at the same time motor 61 is reversed.

The loader as shown can be used for loading boxes, pallets or items intofixed storage areas as well as into trailers. The conveyors 17 and 14also can use rollers on the tops thereof, if desired.

What is claimed is:

1. A vehicle loading apparatus comprising a support frame, a slidemember movably mounted on said frame, means to drive said slide memberwith respect to said frame and into the interior of a vehicle to beloaded, said vehicle having an end wall, means providing a station onwhich to load pallets onto said slide member, a pusher member mountedfor longitudinal movement on said slide member to move pallets on saidslide member along said slide member into the vehicle to be loaded,means to move said pusher member relative to the slide member to a firstposition wherein any pallets on said slide member will be moved off theslide by said pusher member, said slide member being free to moverearwardly when said pallets engage an object which resists movementthereof as the pallets are moved off the slide member, means to retractsaid pusher member from said first position to permit additional palletsto be placed on said slide member ahead of said pusher member.

2. The combination as specified in claim 1 and sensor means to indicatewhen the spacing in said vehicle is less than the necessay space toinsert additional pallets.

3. The combination as specified in claim 1 and means to raise and lowersaid support frame for said slide member, and means on said slide memberto sense when said slide member contacts a surface in a vehicle to beloaded, said means to sense when said slide member contacts said surfacecontrolling said means to raise and lower said frame to cause levelingof said frame with respect to the vehicle to be laoded.

4. The combination as specified in claim 1 and electrical interlockmeans to control movement of said pusher member in relationship topositioning of pallets on said slide member.

5. The combination as specified in claim 1 wherein said means to movesaid slide member into said vehicle comprise friction drive wheels onsaid slide member, said friction drive wheels normally being freewheeling in one direction to permit said slide member to move rearwardlyout of said vehicle.

6. The combination as specified in claim 5 and means to disable the freewheeling means to permit reverse driving of said friction drive wheels.

7. A vehicle loading apparatus for moving objects into a vehicle,comprising a support table, a slide member movably mounted on saidsupport table, means to selectively drive said slide member into theinterior of a vehicle to be loaded, a pusher member mounted on saidslide member, drive means between said slide and said pusher to movesaid pusher to act between an object on said slide member and said slidemember to move slide object along said slide member into the vehicle tobe loaded, said pusher member traveling to a first position wherein anyobject on said slide member will be moved off said slide member ontosaid vehicle, said slide member moving rearwardly from reactive forcebetween the object and vehicle when said pusher member removes theobject from the slide member, and means to retract said pusher memberfrom said first position.

8. The combination as specified in claim 7 and means to raise and lowersaid support table for said slide member, and means on said slide memberto sense when said slide member contacts a surface in a vehicle to beloaded, said means to sense when said slide member contacts said surfacecontrolling said means to raise and lower said table to cause levelingof said table with respect to the vehicle to be loaded.

9. The combination as specified in claim 7 wherein said means to movesaid slide member into said vehicle comprise friction drive wheels onsaid table, said friction drive wheels normally being free wheeling inone direction to permit said slide member to move rearwardly out of saidvehicle.

10. The combination as specified in claim 7 and roller means rotatablymounted on said slide member to support load members.

11. The combination as specified in claim 7 wherein said pusher memberis slidably mounted on said slide member, and positioned to engageobjects on said slide member, said drive means and means to retractcomprising a chain drive mounted on said slide to move said pushermember in a repeating path along the length of said slide member in afirst direction and to reverse said movement of said pusher when thepusher member has reached its first position to return said pushermember toward a second end of said slide.

2 3 3 UNITED STATES PATENT OFFICE CERTKFICATE 0F CCRRECTION Patent: No.3 ,727;777 Dated April 17 1973 Inventor(s) gl e Hanson It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 3,. line 16 "norton" should be--Norton--o Column 5, line 26 "slidshould be--sl:i de--. Column 6, line 32 "psher" should be "pusher".Column 7, line 20 "slid" should be--slide--; Column 7, lines 66 and 67"swtich" should be--switch--. Column l0, line 49 (Claim 3, line 8)"laoded" should be --loaded--; Column 10, line 34 (Claim 1, line 16),before "means insert--and--. Column 12, line 9 (Claim 10, line 3) "loadmembers" should be--said,object---.

Signed and sealed this 19th day of March l97h.

( SEAL) Attest:

EDWARD MOFLETCHER, JR, C. MARSHALL DANN Attesting Officer Commissionerof Patents

1. A vehicle loading apparatus comprising a support frame, a slidemember movably mounted on said frame, means to drive said slide memberwith respect to said frame and into the interior of a vehicle to beloaded, said vehicle having an end wall, means providing a station onwhich to load pallets onto said slide member, a pusher member mountedfor longitudinal movement on said slide member to move pallets on saidslide member along said slide member into the vehicle to be loaded,means to move said pusher member relative to the slide member to a firstposition wherein any pallets on said slide member will be moved off theslide by said pusher member, said slide member being free to moverearwardly when said pallets engage an object which resists movementthereof as the pallets are moved off the slide member, means to retractsaid pusher member from said first position to permit additional palletsto be placed on said slide member ahead of said pusher member.
 2. Thecombination as specified in claim 1 and sensor means to indicate whenthe spacing in said vehicle is less than the necessay space to insertadditional pallets.
 3. The combination as specified in claim 1 and meansto raise and lower said support frame for said slide member, and meanson said slide member to sense when said slide member contacts a surfacein a vehicle to be loaded, said means to sense when said slide membercontacts said surface controlling said means to raise and lower saidframe to cause leveling of said frame with respect to the vehicle to belaoded.
 4. The combination as specified in claim 1 and electricalinterlock means to control movement of said pusher member inrelationship to positioning of pallets on said slide member.
 5. Thecombination as specified in claim 1 wherein said means to move saidslide member into said vehicle comprise friction drive wheels on saidslide member, said friction drive wheels normally being free wheeling inone direction to permit said slide member to move rearwardly out of saidvehicle.
 6. The combination as specified in claim 5 and means to disablethe free wheeling means to permit reverse driving of said friction drivewheels.
 7. A vehicle loading apparatus for moving objects into avehicle, comprising a support table, a slide member movably mounted onsaid support table, means to selectively drive said slide member intothe interior of a vehicle to be loaded, a pusher member mounted on saidslide member, drive means between said slide and said pusher to movesaid pusher to act between an object on said slide member and said slidemember to move slide object along said slide member into the vehicle tobe loaded, said pusher member traveling to a first position wherein anyobject on said slide member will be moved off said slide member ontosaid vehicle, said slide member moving rearwardly from reactive forcebetween the object and vehicle when said pusher member removes theobject from the slide member, and means to retract said pusher memberfrom said first position.
 8. The combination as specified in claim 7 andmeans to raise and lower said support table for said slide member, andmeans on said slide member to sense when said slide member contacts asurface in a vehicle to be loaded, said means to sense when said slidemember contacts said surface controlling said means to raise and lowersaid table to cause leveling of said table with respect to the vehicleto be loaded.
 9. The combination as specified in claIm 7 wherein saidmeans to move said slide member into said vehicle comprise frictiondrive wheels on said table, said friction drive wheels normally beingfree wheeling in one direction to permit said slide member to moverearwardly out of said vehicle.
 10. The combination as specified inclaim 7 and roller means rotatably mounted on said slide member tosupport load members.
 11. The combination as specified in claim 7wherein said pusher member is slidably mounted on said slide member, andpositioned to engage objects on said slide member, said drive means andmeans to retract comprising a chain drive mounted on said slide to movesaid pusher member in a repeating path along the length of said slidemember in a first direction and to reverse said movement of said pusherwhen the pusher member has reached its first position to return saidpusher member toward a second end of said slide.